Storing an arm or a leg of a saint beneath an altar is a longstanding Christian tradition. Based on a passage from the Book of Revelation, this practice became a vital part of Christian ritual in the eighth century, when the Seventh Ecumenical Council of Nicea determined that every altar should contain a relic. Churches in turn performed the function of a giant reliquary, built to house and protect the remains of holy men and women.

The intimate relationship between rituals, like the consecration of an altar by depositing a relic in its casing, and the space in which those rituals took place, is apparent in the development of the annular crypt. Comprised of a semicircular space, buried partly beneath the choir of a church, annular crypts allowed pilgrims to process around a saint's remains below, without disturbing the liturgy above.

Based in part on the changes that Pope Gregory the Great introduced to the tropaion of Saint Peter in Rome in the sixth century, annular crypts became a regular feature of church architecture in the ninth century. The annular crypt, however, was only solution to accommodate the growing number of pilgrims. Another was to add chapels along the side of the nave, allowing for multiple altars within the same structure.

Multiple altars typically entailed multiple saints, although a single altar might contain the remains of many saints, as in the case of the portable altar from Hildesheim said to contain the bones of forty holy men and women. Used to celebrate the Eucharist in situations where one might not have ready access to a church, portable altars maintained the connection between ritual and performance in their design, with many assuming the appearance of a church, albeit one constructed on a much smaller scale.